Smooth muscle cell (SMC) proliferation is a critical event in the pathogenesis of atherosclerosis and transplant arteriosclerosis as well as in the response to injury arising from all forms of vascular reconstruction such as angioplasty (Raines E. W.; Ross R. Br. Heart J. 1993, 69 (Supplement), S 30; Clowes, A. W.; Reidy, M. A. J. Vasc. Surg 1991, 13,885; Isik, F. F.; McDonald, T. O.; Ferguson, M.; Yamanaka, E.; Gordon Am. J. Pathol. 1992, 141, 1139). However, clinically effective inhibitors of smooth muscle cell proliferation for use as antirestenotic agents have not been successful to date (Herrman, J. P. R.; Hermans, W. R. M.; Vos, J.; Serruys P. W. Drugs 1993, 4, 18 and 249).
Reendothelialization of the injured area concurrent with smooth muscle cell proliferation is a major consideration for inhibiting restenosis (Casscells, W. Circulation 1992, 86, 722; Reidy, M. A.; Lidner, V. in Endothelial Cell Dysfunctions, Simionescu, N. and Simionescu M., Ed. Plenum Press, NY N.Y., (1992), 31). Thus, any successful approach to inhibiting SMC proliferation should not interfere with endothelial cell repair or the normal function of other cell types (Weissberg, P. L.; Grainger, D. J.; Shanahan C. M.; Metcalfe, J. C. Cardiovascular Res. 1993, 27, 1191).
The glycosaminoglycans heparin and heparan sulfate are endogenous inhibitors of SMC proliferation, yet are able to promote endothelial cell growth (Castellot, J. J. Jr.; Wright, T. C.; Karnovsky, M. J. Seminars in Thrombosis and Hemostasis 1987, 13,489; Wight, T. N. Arteriosclerosis 1989, 9, 1). However, the full clinical benefits of heparin, heparin fragments, chemically modified heparin, low molecular weight heparins, and other heparin mimicking anionic polysacchafides may be compromised due to other pharmacological liabilites (excessive bleeding arising from anticoagulation effects, in particular) coupled with heterogenity of the various preparations (Borman, S. Chemcial and Engineering News, 1993, June 28, 27; Schmid, K. M.; Preisack, M.; Voelker, W.; Sujatta M.; Karsch, K. R. Seminars in Thrombosis and Hemostasis 1993, 19 (Suppl. 1), 155; Amann, F. W.; Neuenschwander, C.; Meyer, B. Seminars in Thrombosis and Hemostasis 1993, 19 (Suppl. 1), 160; Radhakrishnamurthy, B.; Sharma, C.; Bhandaru, R. R.; Berenson, G. S.; Stanzani, L.; Mastacchi, R. Atherosclerosis, 1986 60, 141; Maffrand, J. P.; Hervert, M. M.; Bernat, A.; Defreyn, G.; Delevassee, D.; Savi, P.; Pinot, J. J.; Sampol, J. Seminars in Thrombosis and Hemostasis, 1991, 17 (Suppl. 2), 186). Since the anticoagulant effects of many of these agents are independent of SMC antiproliferative activity, it would be expected that polyanionic agents which are more homogenous in composition and of more defined molecular structure would exhibit a more desirable and balanced profile with fewer side effects associated with aforementioned anionic polysaccharides.